Well tool



Sept. 22, 1942.

TXT

Z0 I ff A. MUHLBACH WELL TOO Filed May 8, 1940 TV1- f 3 Sheets-Sheet l INVEN'TOR.

` ATTOKNEYJ Sept. 22, 1942.

A. MUHLBACH 2,296,397v

WELL TOOL Filed May 8, 1940 5 Sheets-Sheet 2 Z y Tij@ Z ifi Tiff RWM m ATTORNEY Sept. 22, 1942. A. MUHLBACH.

WELL TooL Filed May 8. 1940 5 SheetSSheet 3 INVENTOK 4A/M4 Muy/@r 23% ggd/wd A T TO KN E Y Patented Sept. 22, 1942 UNITED STATES PATENT OFFICE WELL TOOL Alfred Muhlbach, Los Angeles, Calif.

Application May 8, 1940, Serial No. 333,983

11 Claims.

This invention relates to a device adapted to be lowered into a well that is being drilled, to cooperate with tools or other apparatus, in the Well. Such tools so positioned are often without means of conveniently raising them to the surface. The present device can form a connection therewith, bymeans of which the tool or apparatus may be brought to the surface. Such `'devices are known and are commonly termed overshots.

In present day drilling practice, wire line core barrels are frequently used. Such core barrels are detachably secured in the end of the drill string so as to be rotated and advanced therewith and are removed` whenever desired by means of a tool or overshot which is lowered in the drill string on a cable, and is adapte-d to grasp the top of the core barrel by any of various types of latching means.

It sometimes happens that the Core barrel or other apparatus becomes stuck in position in the well or casing, as for instance, due to small rocks wedging about the apparatus, or other causes. When this occurs, the wire line and overshot are in the drill pipe and can not be removed, since they have been attached to the core barrel. At the same time their presence there seriously impedes any steps it may be desired to take to loosen the core barrel or other apparatus so that it can be removed. Frequently, eiiorts to lift a stuck core barrel result in parting the wire line, after which there is nothing to do but remove the entire drill string, which is always an expensive job, usually attended by considerable risk.

By the aid of the present invention, the connection between the wire line and the core barrel, or other apparatus which it is desired to lift, is arranged to be broken when the pull on the cable reaches some predetermined amount, well within the capacity of the cable. Thus, if it is not possible to move the core barrel or sh without endangering the cable, the overshot is released and together with the cable is removed from the Well, when appropriate steps to loosen the core barrel may be taken readily.

It is accordingly one of the objects of this invention to provide an overshot capable of releasing its grip in response to a pull of a predetermined magnitude.

It is another object of this invention to provide a releasable overshot which is strong, simple and durable.

It is still another object of this invention to providea releasable overshot in which the pull acts directly to release the overshot, after this pull has reached a certain magnitude.

It is still further an object of this invention to provide an overshot in which the overshot is released in response to the shearing of a pin by the lifting force exerted on the overshot.

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of several embodiments of the invention. For this purpose there are shown a few forms in the drawings accompanying and forming part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

In the drawings:

Figure 1 is a longitudinal section through a tool, embodying the invention, and connected to the upper end of a core barrel or other apparatus preparatory to lifting it from the well;

Fig. 2 is a sectional View, on an enlarged scale, taken on plane 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1, but showing the tool just after it has released the core barrel;

Fig. 4 is a View similar to Fig. 1 but showing a modified form of the invention;

Fig. 5 is a sectional View, on an enlarged scale, as seen on plane 5-5 of Fig. 4;

Fig. 6 is a View showing the tool of Fig. 4 just after releasing the core barrel;

Fig. 7 is a fragmentary view similar to Fig. 4, but showing a further modied form of the invention;

Fig. 8 is a View showing the operation of resetting the tool of Fig. 1; and

Fig. 9 is a section as seen on plane 9 9 of Fig. 8.

Referring to the form of the invention shown in Figs. 1, 2 and 3, the tool or overshot is generally indicated by l and is suspended from a wire line or cable 2 provided with a suitable socket 0r threaded member 3. A sinker bar 4 to insure the tool traveling downwardly through the mud may be lifted out of the well by means of cable 2. Such arrangements are known; however, it will be apparent that in event it is not possible to move the core barrel, it is desirable to be able to release the jaws so that the cable 2 and tool I may be removed.

To make such removal possible, the tool I has a body I6 within which a mandrel II is telescopically mounted for limited longitudinal movement with respect thereto. The arrangement is such that when there is relative axial movement of the mandrel in the bore I6 of body I9, the jaws 5, 6 carried by the mandrel are released from shoulder 8. Normally such relative movement of the mandrel II and the body I6 is pre- I.

vented, since they are joined by a releasable or frangible connection, such as shear pin I2. 'The lifting force exerted by cablev2 is transmitted to the mandrel I I and hence to core barrel 9 by this connection. If the core barrel is not readily moved, when the force exerted by Acable 2 becomes sufficient to fracture the connection I2, mandrel I'I is permitted to-y move to-its extended position (Fig. 3) and the jaws 5, Y6 release the core barrel 9,;in a manner now to be described.

Body I has a threaded tapered pin I5 at its upper end by means of which `the tool is lattached to the cable 2, and its bore I6 extends toits lower end. The upper part I I of mandrel ,II `is slidable within bore I6. Thelower-portion of mandrel II is provided with a vbore orbowl vI8 intersected by slot I9, the latter accommodating jaws and 6 which are pivoted on pin 29 in Athe mandrel II. Jaw members 5 and 16 each have .upward extensions 2| and v22 between which'spring I is accommodated and are provided with exterior inclined or cam surfaces 23 and `2li. Jaw membersg5 and-6 also have downward extensions 25 and 26, each provided with an inwardlyand upwardly directed hook 2'I, 23, adapted Yto enter bowl I8.

The upper end of the core barrel or other apparatus 9 is shown ashaving a tapered portion 16, terminating ina neck gII of'relativelysmall diameter and surmounted by a head 1 2, thus forming shoulder 8. 'Ihetopof head 1 2 is Vconvex yas indicated-by 'I3 and-thelower end ofibore I8 is flared outwardly as'indicated'by 14. -Thus, as the lower end of the toolI contacts head'IZ, surfaces 'I3 and I4 cooperate to guide'thetoolinto coaxial position with apparatus'g so that Vhead 'I2 enters bowl I3 and ,engages jaws .5 and.6. Continued lowering of Itool I causes thejlower inclined surfaces 'I5 and-'I6r of thejaws 5,16 to ,engagehead 12, andthe jaws are forced apart. Thus the jaws pass downwardly over the head until thehook portions 2'I and 26 are vforced under shoulder 8 by spring I.

A collar 39 is mounted on the outsideof body I6, being secured against longitudinal movement on the body by pin I2, which pin, as clearly shown in Fig. 2, passes through body I I), mandrel and collar 3l), preventing relative movement between them. A second collar 3| Valso on the outside of body Il] is secured against movement with respect to mandrel II by a pin 32. As clearly shown in Fig. 2 this pin 32 extends through mandrel II, body I9 and ring 3|, but is.. utilized to form a lost motion connection between `the mandrel and the body by the provision ofslots 33 in the body II).

A compression spring V34 isconned ,between collars 316 and 3|. 'It will be plain that relative movement between these collars-is preventedby their being secured to mandrell I byipins' 2 and 32 respectively. However, if pin I2 is fractured, collar 30 will be forced downwardly on the mandrel |I, the lower'edgeiof Ycollar 39 riding downwardly on surfaces 23 and 24 forcing jaws 5 and 6 to the disengaged position of Fig. 3.

From a consideration of Fig. 2, it will be clear that any upward force exerted as by cable 2 on body I0 is transmitted to the mandrel II, and hence to whatever is anchored between the jaws 5,6, solely through the connecting pin I2. When this force is sufficient to fracture this pin, body I6 moves upwardly on mandrel I I until the lower end of slots 33 engage pin 32 (see Fig. 3). At the same time, collar 39 being freed of the restraint of pin I2 is forced downwardly of the mandrel by spring 34 and swings jaw mem- Yber v5,6, about their pivot 26 to free hooks 21,

fromshoulder 8. The tool I may now be withdrawn from the well, and suitable steps taken to loosenthe core barrel or other apparatus 9. The parts of tool I may be readily returned to their initial ,relative positions, and a new pin I2 inserted, after which the tool is ready for further use.

A convenientmeansof compressing the operating spring Y34, so .that the tool may bereset .and a new pin |2 replaced Ais provided by the arrangement shown in Figs. .8 and 9. Therein a plate is provided with a Ushai3d .opening 9| just large enough to accommodate the mandrel II Ybelow collar 39. Plate 99 may be Asupported in any convenient manner, as for example Abya section of pipe 92 partly cut away to receive the tool as at 93 and provided witha base 94.

While the tool I is attached to cable 2 and sinken bar 4, it is inserted transversely into pipe 192 through opening 93, the lower end of collar 3 9 beingslightly above plate 9 0. Tool I is then lowered so that collar 30 restsonplate 99, .the

weight of sinkerbar 4 being sufficient to compress` spring34 toits initial condition and allowing all parts to return to their original position as shown in Figql. ,A newpin I2is thenpassed 'through collar 3|), mandrel I I and body I6 to ,retain them in posiQn- .This 121x112 maybe retaned'in place in any Convenient wenas by riveting over the endsslightlr "In the form lof the Y invention illustrated .Fiese 5 and. the ,tOQlx-iiisattached-to a @able v2 in the same manner as before, and is arranged tograsp the core barrel por other ,apparatus .9 by apar of'pivoiediiawmemhers ,5l ,and 15,2 ina similar manner.

'T001'.50 comprises .a `bojdy.lnnerirlber ,5.3. attached to cable 2, having a bore 54 within which is slidably mounted a mandrel55 .carrying the jaws 5|,152 in a slot in ,its lower portion. 4Apin156 secured in body53 engagesaslot'l themandrel providing a lostmotionconnection vbetween the body and the mandrel. yA shear pin5 |3fre leasablymsecures, the mandrel 55 `to body. v5.3 4,at-the upper limit ofthe movement permitted by the slot and pin connection 51,56,

Body 53 has a vskirt Vor lextension ..60 .which encircles the upper portions,.6|,.62fof vvjaw-members 5I, 52. These portions6I, 62 havelobesfor cheeks 63, v6,4, providingv cam Ysurfaces 65, A66. Skirt ,66 has openings IiI and r68v to accommodate lobes 63,64 respectively, thelower edges oil-these openings being adapted to cooperate -withcam surfaces 65, 66. A'

With bOdy Y53 1andmandrel55 locked. together by pin 58, jaw members 5I and.52.are"fr,eeto swing vapart to receive the head I. 2I andftoclose in response-to compression spring -69 to ,engage shoulder 8. 's 'long as the upward pull exerted by cable 2 'is not sufficient to fracture the pin 58, the jaws will remain engaged with the shoulder 8, and under normal conditions the core barrel or other apparatus 9 may thus be lifted out of the well. If, however, this force becomes eX- cessive and the pin 58 is fractured, body 53 will slide upwards on mandrel 55 until stopped by the engagement of pin 56 with the top of slot 51.

This relative movement between body 53 and mandrel 55 causes the lower surfaces of openings 61 and 68 to act on surfaces 65, 66, forcing the upper portions of jaw members 5I and 52 inwardly and swinging the lower portions outwardly land free of shoulder 8. The tool 50 is thus entirely disconnected from the core barrel 9 and may be removed from the well.

In the modification shown in Fig. 7, a spring retainer is provided to maintain the mandrel and body against relative movement until the force tending to cause this movement reaches a predetermined amount. Thus, mandrel 8|] is substantially identical with mandrel 55; it carries jaw members 5| and 52 and is connected to the body 8| by a lost motion connection 56, 51 all as before. The exterior of mandrel 80 has a circumferential groove 82 which registers with an internal groove 83 in body 8|, when the body and mandrel are positioned to permit jaws 5|, 52 to close. A split ring, or snap ring 84 is disposed in groove 83 and due to its resilience embraces mandrel 83 and engages groove 82. Due to the simultaneous engagement of grooves 82 and 83 by ring 84, relative motion between the body 8| and mandrel 80 is prevented. The up# per and lower surfaces of groove 82 are bevelled, as indicated by 85, 86. The inner portions of the end surfaces of ring 84 are similarly bevelled, thus upon the exertion of suflicient upward force on body 8|, assuming mandrel 80 being xed to resist it, ring 84 will be forced out of groove 82 so that it is entirely in groove 83, allowing the body to slip upwardly along the mandrel. This produces the same result as the shearing of pin 58.

This form of the tool may be reset by suitably supporting the lower end of the mandrel 80 and applying a downward force on the body 8|, as by the weight of sinker bar 4. When ring 84 is out of engagement with groove 82, it is only necessary to apply sufficient force on the body 8| to overcome the friction'al grip of ring 84 on mandrel 80 to cause relative movement. Hence, a force much smaller than that necessary to trip the tool suffices to reset it.

To permit the installation of ring 84 in the first place as well as its removal and replacement, body 8| is divided into sections 81 land 88 at groove 83, these sections being joined by the threaded connection 89.

What is claimed is:

l. In a device of the character described, a body adapted for longitudinal movement in a well bore, a mandrel carried by the body and in telescopic relationship therewith, said mandrel extending below the body and forming a bowl, open at the bottom, adapted to be placed over apparatus in a well, a releasable connection between the body and the mandrel to prevent relative movement therebetween, jaw members carried by the mandrel below the body and adapted to engage said apparatus so that said apparatus may be lifted from the well with said body, and means operative upon release of said releasable Cil connection to disengage the jaw members from the app-aratus, said releasable connection being adapted to permit relative movement between the body and the mandrel when the upward force exerted on the body reaches a predetermined amount.

2. In a device of the character described, a body adapted for longitudinal movement in a well bore, a mandrel carried by the body and in telescopic relationship therewith, a releasable connection between the body and the mandrel to prevent relative movement therebetween, a pair of jaw members pivotally mounted on the mandrel, said jaw members having downward extensions adapted to move inwardly to engaging position, said members also having upward extensions with cam surfaces formed thereon, and a member having surfaces arranged to cooperate with said cam surfaces and movable along the mandrel upon release of said connection, said movement causing the jaw members to swing about their pivots and move the downward extensions out of engaging position.

3. In a device of the character described, a body, a mandrel having a bowl, open at the lower end of the mandrel, jaw members pivotally carried by the mandrel and adapted to engage an object in the bowl, spring means urging the jaws to engaging position, a member slidable on the mandrel and arranged to disengage the jaws, a shear pin for securing the member to the mandrel as well as for securing the mandrel to the body, and means forming a lost motion connection between the body and the mandrel to limit motion therebetween upon fracture of the shear pin.

4. In a device of the character described, a body having a bore, a mandrel having an extension slidable in said bore, a bowl at the lower end of the mandrel, jaw members pivoted in the mandrel and having depending extensions with respectively upwardly and oppositely directed hooks, resilient means urging the jaws about their pivots, so that the hooks enter the bowl, the jaw members also having upward extensions with cam surfaces thereon, means forming a cam follower movable with respect to the body and adapted to urge the jaw members about their pivots so that the hooks move away from each other and out of the bowl, means to move said follower with respect to the body, and means to prevent said movement until the force tending to cause` relative movement between the body and the mandrel reaches a predetermined value.

5. In a device of the character described, a body arranged for longitudinal movement in a well bore, a mandrel, a frangible connection between the body and the mandrel for transmitting a lifting force from the body to the mandrel, means pivotally secured to the mandrel arranged to engage an object to be lifted in the well bore in response to upward movement of said body, means to disengage said last mentioned means upon breaking said connection and operated by continued upward movement of the body, and supplemental means to transmit the lifting force fromthe body to the mandrel after said connection is broken.

6. In a device of the character described, a body arranged for longitudinal movement in a well bore, a mandrel, a frangible connection between the body and the mandrel for transmitting a lifting force from the body to the mandrel, means pivotally secured to the mandrel arranged to engage an object to be lifted in the well bore in response to upward movement of said body, a member movable upon said mandrel iipvon breaking said connectionto' disengage said engaging means'supplemental means to'trans-v mit the lifting force from the body to the mandrel after said connection is broken, said frangible connection also serving to prevent relative moyement between the member and the mandrel'. 7,'In a device of the'character described, a body arranged for longitudinal movement in av well bore, amandrel, a frangible connection be` tween the body and the mandrelV for transmitting a lifting force from the body to the mandrel, means p votally secured to the mandrel arranged to engage an object to be lifted inthe well bore in response to upward movement of said body, said body being upwardly Vmor/"able upon said mandrel to release 'said engaging means.

'8; Ina de'vice'of the character described, a mandrel;A spring operated jaws pivoted on the mandrel and having cam surfaces, a member adapted for longitudinal movement along the mandrel, and hai/ing a surface to cooperate with the cam surfaces,`,upon such longitudinal movement to swing the jaws against the spring, means for 'exerting an upward pull on the mandrel and a shear pin through'y which such pull is exerted, said shear pin alsoserving to prevent longitudinal movement between the member and the mandrel, until said pin is sheared by said pull.

' 9. An overshot for retrieving'a wire line core i barrel including a member having a bowl adapted to receive a head' formed on thecore barrel, saidl head having a downwardly directed shoulder, latch means carried by 'said member and,

adapted to engage said shoulder when the head passes into said bowl, a body slidable with respect to said member, a collar slidable with respect to the member, `a fran'gible' connection between the body, the member and the collar to prev nt 'relative' movement therebetween, means ad pted to ca'us'e the" collar 'to' s'lideon said member "and release' the latch means upon vfracture rsid" cnn'eetion, and 'means' forming a 10st motion connection between the body and the member t restrict relative motion between them after said connectionis" fractured. 10'. Ani'oversh'ot for retrieving a wire line core barrel'inclilding'a memberhaving a bowl adapted'to receive ahead" formed on" the core barrel, said headhaving' a downwardly directed shouldeii latch means carriedJ by' saidr member and ,gicle-ipte'dl to ye'n'gafg'e'said shoulder when the head plasse' 'into 'sa-id"bowl,v a body 4slidable lwith respect to said member, said' body having an e'X'- tension alvoiit'said memberahd engaging the latch means,l said extension being adapted to disengagdthe "latchmeans' from said shoulder 'irir'elative movement between the body and .h'inember, a frang'ible connection between the body 'andthe member 'to' prevent such relative movement, and'means' to restrict movement be- .tween the body and the member after said frangible connec'tion'is broken.

` '11. In "adevice of the character described, a body, a mandrel carried b-yV the body and arranged fr limited Vlongitudinal movement relative"` thereto, means carried by the mandrel for engaging a device in a well and normally urged t 'engaging "position, means operative upon relaltive movement betv'veenthe body andthe mandrel t move thenvgaging means to disengaging position, and a resilient member joining the mandrel to the AAbody to prevent such movement until' the force tending to cause sich movement reaches a predetermined amount.

vALFRED MUHLBACH. 

